Helical Pile w/ Cap Above Frost Line

[EGuenth]

I'm working on a project where I'm implementing a helical pile to avoid a high water table and an existing drain tile. We're planning on placing a concrete pile cap at the top. Due to interference of the drain tile, the plan is to pour the concrete above the code required frost line of 42".

I have seen the use of void forms and/or EPS below pile caps to prevent frost heave on the cap, but I can't find any references or additional information on this practice. Is anyone familiar with anything like this? Any help is much appreciated.

 

[jayrod12]

you might also want to consider sleeving the pile cap to avoid the adfreezing (frost jacking). The frost will actually grab the sides of the pile cap and push up.

Void form below the pile cap will prevent uplift forces due to the soil heaving but will not prevent the adfreezing.